Kerfing machine



July 10. 1956 c. o. BJORK KERFING MACHINE 2 Sheets-Sheet 1 Filed Aug. 18, 1955 INVENTOR. (4/91 0. BJfizQ/Q Y z A m y 10, 1955 c. o. BJORK 2,753,900

KERFING MACHINE Filed Aug. 18, 1955 2 Sheets-Sheet 2 IN V EN TOR.

(421 a Avae BY g g [441i United States Patent KERFING MACHINE Carl 0. Bjork, Tumwater, Wash., assignor to St. Paul &

Tacoma Lumber Company, Tacoma, Wash., a corporation of Washington Application August 18, 1955, Serial No. 529,148 Claims. (Cl. 144-136) This invention relates to a kerfing machine and, more particularly, is concerned with a machine for simultaneously cutting uniform kerfs in long, thin and narrow furring-strips.

It has become increasingly customary in the application of siding to houses and other building structures to employ boards of uniform thickness such, for example, as boards cut from larger sheets of plywood. In order to obtain the drop-siding effect previously produced by taper cutting the boards, in modern practice this uniformly thick siding is given the sloping appearance of tapered drop siding through the use of a furring-strip attached to the wall surface at or near the bottom edge of the board applied thereover. Thus, when the board is applied so that its bottom edge is spaced outward from the wall, the thickness of the furring-strip and its upper edge is brought into juxtaposition with the supporting wall and the outer face will slope relative to the vertical. The use of such furring-strips makes it possible to economically and practically ventilate a wall and permit the egress of moisture from within the wall to the surrounding air, or oppositely, as the case may be. This is easily accomplished by cross-cutting a broader face of a long, thin furring-strip with a saw kerf extending partly through the thickness of a strip at spaced intervals along the length of said strip. When said strip is applied to the wall in a horizontal manner, air passages will be left between the furring-strip and wall or between the furring-strip and the overlying siding board in accordance with choice of application of the workman.

It has been among the more important objects of this invention to provide a machine for kerfing such long, thin and narrow fuming-strips; to provide a machine capable of doing so in a substantially continuous manner; to firmly but simply hold such furring-strips during kerfing to avoid splitting and to insure uniform cutting; and to accumulate quantities of kerfed furring-strips in a manner suitable for bundling and for rapid tying whereby the attendants of such a machine may also service the machine and keep it supplied with uncut furring-strips as well as off-bear the tied bundles.

These and other objects of the invention will be apparent from the following specification when read in the light of the accompanying drawings in which is shown a preferred construction of my kerfing machine.

In the drawings:

Figure 1 is a perspective view of my kerfing machine;

Figure 2 is an enlarged vertical sectional view taken in the plane suggested by line 22 of Figure 1;

Figure 3 is a vertical elevational view to enlarged scale with portions omitted for convenience of illustration showing a furring-strip transfer wheel and reciprocal means employed for advancing a kerfed furring-strip away from the transfer wheel;

Figure 4 is a fragmentary detailed view illustrating a means for holding a furring-strip to a transfer wheel during lateral movement thereby;

2,753,900 Patented July 10, 1956 Figure 5 is a detailed view in side elevation of the furring-stn'p ejecting and advancing means, and

Figure 6 is a fragmentary perspective view of a furring-strip kerfed according to my machine.

The furring-strip 10 shown in Figure 6 is usually a wooden strip having the approximate dimensions, for example, as follows: thick, 1 /2" wide, with cross-kerfings 12 spaced approximately 16 inches apart and preferably having the first kerf from the end spaced therefrom a distance of 8 inches. The kerfs are ordinarily the thickness of a saw blade in width and cut to a depth of one-third to one-half the thickness of the furring-strip. It will be understood that the dimensional specifications given herein are purely exemplary and that strips of different widths and different thicknesses and with kerfs at different intervals may likewise be accommodated according to this invention without departing from the spirit thereof.

The kerfing machine shown in Figure l is incorporated in a frame comprising the inverted Y-shaped end sections 14 and 16 that are joined together by longitudinal structural members 18, 19, 20, 21, 22 and 23. Each of the end sections comprises a pair of legs 24, 25 that tend to converge as they rise from the floor, and include upstanding parallel arm portions 26 and 27, respectively. The upwardly extending arms 26 and 27 of end frame section 14 are spaced apart and no cross member or other obstructing element is disposed between them. The upstanding members 26 and 27 of the end frame section 16 are separated by head block 28. Pairs of guide bars 29 and 30 are secured at their upper ends to members 22 and 23 and at their lower ends to members 20 and 21. These, together with the other structural members, form a magazine chamber for containing a stack M of tuningstrips. In the magazine the furring-strips are stacked in face-to-face relation. They are placed there from above through the end opening between the upstanding arms 26, 27 of frame 14. They are withdrawn from beneath the stack M in a manner later to be described.

A main wheel shaft 32mounted in bearings 34, 35 extends the length of the machine beneath the stack M and has mounted thereon, spaced at intervals along its length, a plurality of transfer wheels 36. As shown in Figure 2, the charge M of furring-strips in the magazine rests on the upper peripheries of wheels 36. Each wheel has a plurality of radial shoulders 37 adjacent the carrier flats 38. As each such shoulder 37 travels in its annular path, it will engage the bottommost furring stn'p of stack M which is resting upon the wheels. This causes a furring-strip to be picked up for arcuate lateral transfer, as to the right in Figure 2, past the kerfing saw 40. A series of saws 40 is mounted on saw arbor 42, which in turn is mounted in bearings 44 suitably supported in cantilever fashion from the frame by means of brackets 45. The spacing between the outer edge of the saw teeth of the saws 40 and the peripheries of wheels 36 is such that a furring-strip carried thereby is kerfed as shown in Figure 6.

The machine is activated through power derived from motor 50 mounted on shelf 52 and which drives shaft 54 and sheave 56 thereon. Through travel of transmission belt 58 sheave 60 on the arbor 42 is rotated. A transfer belt 62 transmits power to sheave 64 to drive belt 66 and sheave 68 on the wheel shaft 32.

Extending across the machine, substantially horizontally, are table arms 70 which serve as table means to receive the kerfed furring-strips as they are transferred arcuately past the kerfing saws 40 to a downward position where the furring-strip is disengaged from the transfer wheel 36 and shifted laterally on the table arms 70. Such is accomplished by means of a reciprocal lug 72 carried by slide arm 74 which is suitably mounted for sliding reciprocal motion on a side of a table arm 70.

Reciprocation of arm 74 is obtained through the instrumentality of rock arm 76 which depends from pivot pin 78, in bracket 80. The lower end of arm 76 is connected by means of a lost-motion slot to arm 74 through the instrumentality of the cross pin 82. A spring 84 is attached at one end to pin 82 and is anchored at its other end to arm member 70. Between pins 78 and 82, arm 76 carries a cam-follower roller 86 which is periodically engaged by one of the several camming surfaces of cam wheel 88. The design of the cam 88 is such that arm 76 is gradually and slowly caused to swing in a rearward direction, thus gradually tensing the spring 84. At the correct instant, in time with the arrival of the furringstrip close to the upper surface of the table arms 70, the slide arm 74 is released and lug 72 is rapidly propelled forward under the action of spring-84. This action dislo'dges and ejects the furring-strip from in front of the shoulders 37 of the transfer wheels 36 and rapidly shifts or advances the same to the right as in Figure 2. The lug is again withdrawn prior to the arrival of the next furring-strip.

A pair of L-shaped arms 90 are cantilevered from frame member 21 so that their lower outstanding ends overlie the table arms 70. The lateral shifting of a furring-strip by lug 72 presses the furring-stripinto the space between the overhanging portion 91 of arm 90 and table arms 70. In so doing, an entire group of previously accumulated furring-strips in advance thereof is likewise shifted laterally. A pair of spring-pressed pivoted latches 94 and 96 is provided adjacent the mouth formed by overhanging arm portion 91 and the shelf 70. As shown in Figure 5, the lateral shift of the furring-st'rip displaces the latches 94 and 96 upwardly and downwardly, respectively, until the strip is in such a position that the latches may close together again. Latches 94 and 96 function to prevent backward tilting or other rearward movement of the furring-strips.

When a suitable number of furring-strips has been accumulated upon the arms 70, the attendants of the machine will manually shift the same from the accumulating throat beneath the arm portion 91 to the side where they are tied with cords C into a tight, easily handled bundle B.

As shown in Figure 4, a presser blade 98, supported from the structural member 21, lies adjacent the path of movement of the furring-strips from the upper position where they are picked up from the magazine toward the discharge position from the transfer wheel. This path naturally includes that portion during which the furringstrip is kerfed. The outer face of the furring-strip intermediate the saws is engaged by the inner surface of the blade 98 and the same functions to hold the furring-strips against the flats 38 of the wheels 36.

Operation To summarize the operation of the machine, it will be apparent from the foregoing that initially the bottommost furring-strip in stack M is deposited on a transfer fiat 38 ahead of shoulder 37 on each of the wheels 36 of the series of transfer wheels and is caused to be arcuately transferred laterally from the pick-up point, by means of rotation of the transfer wheels. During such transfer the moving furring-strip travels past the saws 40 and is provided with kerfs 12, as shown in Figure 6. At the time of cutting the farting-strip, it is being advanced forwardly in the path by shoulders 37 and is riding on the flats 38, being held there by blades 98 which restrain the furringstrip and prevent it from assuming a distorted position in the machine, as well as to prevent it from being disengaged from in front of the shoulders 37.

As the transfer wheels 36 continue to rotate and carry the furring-strip past the saws 40, the'path of the furringstrip becomes more vertical and less lateral due to the curvature of the transfer wheels. in this manner the furring-strip is disposed in an erect or on-edge position, as shown in Figures 2 and 5. By so positioning the furring-strip, the lateral disengagement or dislodgment of it from the notches in wheels 36 is facilitated, since in this position it is most effectively acted upon by the lug 72. When the latter lug moves from the retracted position shown in Figure 2 to the advance position shown in Figure 5, its leading edge presses on the furring-strip. The means by which the lug 72 is advanced and retracted has been previously described.

It will be seen from the foregoing that the objects of the invention set forth initially have been accomplished by a machine which is extremely simple to construct, easy to operate and, in operation, in a continuous manner very efiectively and efiiciently applies several kerfs simultaneously to a series of long, thin, wooden furring-strips. It will be apparent to those skilled in the art that changes and alterations may be made in the construction as well as the operation of this machine. Those changes and alterations which fall within the spirit and scope of the subjoined claims 1 consider a part of this invention.

Having thus described my invention, I claim:

1. A kerfing machine for long, thin furring-strips, comprising: a frame having an aligned series of vertically disposed transfer wheels mounted for rotation about a common axis, means to rotate said wheels, a furringstrip delivery means on said frame to deliver a tuningstrip to said wheels above their axes, said wheels having means to engage the furring-strip for arcuate transfer laterally downward from the delivery point, saw means to cross-kerf said furring-strip during said transfer, table means on said frame in the path of such kerfed furringstrip to receive the same, reciprocal means to engage such furring-strip and to laterally move the same on said table means, and means to reciprocate said reciprocal means.

2. The structure according to claim 1 in which the reciprocal means comprises a lug laterally movable between a position intermediate a pair of wheels and a position laterally outward of the wheel periphery, and the means to reciprocate the same comprises a cam-actuated cam-follower member connected with said lug, and cam means is mounted in said frame for rotation in timed relation to said wheels.

3. A kerfing machine for. long, thin fuming-strips, comprising: a frame having an elongated horizontal shaft mounted for rotation, means to rotate said shaft, 21 series of transfer wheels at spaced intervals on said shaft, a furring-strip magazine on said frame above said wheels to contain a pile of superposed furring-strips in face-t0- face relation, said magazine being open at the bottom and extending parallel to said shaft whereby said pile of strips will rest upon said wheels, said wheels including means to engage and serially withdraw the bottommost furring-strip from such a pile for arcuate transfer laterally therefrom, saw means to cross-kerf said furring-strip during said transfer, table means on said frame in the path of such kerfed furring-strip to receive the same, reciprocal means to engage such furringstrip and to laterally move the same on said table means, means to reciprocate said reciprocal means, and means to maintain said kerfed furring-strips in a group during the accumulation of a suitable number for bundling.

4. A kerfing machine for long, thin furring-strips, comprising: a frame having an elongated horizontal shaft mounted for rotation, means to rotate said shaft, a series of vertical transfer wheels at spaced intervals on said shaft, a furring-strip magazine on said frame above said wheels to contain a pile of superposed furring-strips in face-to-face relation, said magazine being open at the bottom and extending parallel to said shaft whereby said pile of strips will rest upon said wheels, said wheels having shoulder means to engage and serially withdraw the bottommost furring-strip from such a pile for arcuate transfer laterally therefrom, saw means to cross-kerf said furring-strip during said transfer, table means on References Cited in the file of this patent said frame in the path of such kerfed furring-strip to receive the same on edge, reciprocal lug means to engage UNITED STATES PATENTS such furring-strip and to laterally move the same on said 2,574,672 Topham et al Nov. 13, 1951 table means, means to reciprocate said lug means, and 5 means to maintain said kerfed furring-strips on edge dur- FOREIGN PATENTS ing the accumulation of suitable numbers for bundling. 6, 0 Germany Sept. 29, 1920 5. The structure according to claim 4 in which there 435,537 Great Britain p 25, 1935 is included means to hold such withdrawn fuming-strips to said wheel during such transfer, and while the furring- 10 strip is being cross-kerfed. 

